I. Field of the Invention
This invention relates to a method for the production of antibiotics by culturing microorganisms in a culture broth. More particularly, the invention concerns a method for recovering the antibiotic produced from the fermentation broth.
II. Description of the Prior Art
Methods for the production of antibiotics from microorganisms wherein a microorganism is grown in a culture medium or broth and the antibiotic produced by the microorganism is extracted from the broth are well known. Typically, the antibiotic is extracted from the fermentation broth using an organic solvent, such as, ethyl acetate, chloroform, methylene chloride, and the like. However, these organic solvents also extract other materials and components in the broth which are soluble in the solvent resulting in impurities being carried along with the extracted antibiotic. It is thus necessary to remove these impurities before final recovery and/or purification of the antibiotic. The purification processes used heretofore are complicated and expensive and result in increased costs associated with the antibiotic production process.
A typical purification process is described in U.S. Pat. No. 3,116,202 which discloses the purification of the antibiotic streptovaricin using repeated recrystallizations.
A method for increasing the production efficiency of Streptovaricin C is disclosed in U.S. patent application Ser. No. 07/601,815 filed concurrently herewith and claiming priority of Japanese Patent applications 14285/1990 and 14286/1990, the contents of which are incorporated herein by reference, wherein adsorbent polymer beads are added to the fermentation broth to improve the productivity of Streptovaricin C. See also H. Wang, Annals New York Academy of Sciences, 431, 1983, pp.313-321. In these methods, the antibiotic produced from the mold essentially immediately adheres to the polymer beads and for this purpose, the mold is in close physical relationship and contact with the beads in the broth. The polymer beads are generally physically separated from the fermentation broth and adhered antibiotic product must be recovered from the beads. However, components from the broth, including the mold, are carried along with the recovered beads during the separation process resulting in impurities being carried into the resulting mixture, as well as loss of mold and difficulty in recovering the beads for reuse.